The present invention relates to PC memory cards of the type configured to be plugged into a computer system.
PC cards, also known as memory cards and IC cards, are in wide-spread use. These cards are credit card sized peripheral devices with electronic components that can add a wide variety of capabilities, such as memory, mass-storage, LAN, fax/modem and wireless communications to computers and other electronic systems. One or more electrical connectors on the sides of the card are used to connect the card to the electronic systems.
Known PC cards typically include one or more integrated circuits (ICs) or other electrical components mounted to a printed circuit (PC) board. At least one electrical connector is also mounted to the printed circuit board and electrically connected to the electrical components. The PC board is typically supported by a plastic frame. The frame, PC board, and connector are surrounded by a metallic cover; the cover encloses the frame and PC board, while the connectors project from openings in the ends of the cover. The cover typically comprises a top and bottom half, which are held together by a fastening means.
Commercially available PC cards employ various means for fastening the top and bottom covers to each other or to the plastic frame. PC cards manufactured by Elco and Methode have covers which include latches which engage the plastic frame, thus securing the covers to the frame. Duel Systems sells a PC card in which the top and bottom covers are ultrasonically welded together. A card manufactured by IBM uses laser welding to fasten the covers together. PC cards available from AMP, Globe Manufacturing, and Honda have a clamshell design in which a lip or lips on the top cover wrap around the edge of the bottom cover when the card is subjected to high pressure, thus clamping the covers together. The Honda card also uses an adhesive to more securely attach the covers. A similar card manufactured by R&D Micro is assembled by pressing the covers together around the plastic frame, but in this design the top and bottom covers both have lips which latch onto the frame.
Prior art PC card covers, once sealed, are generally not meant to be reopened and reused. However, it is sometimes desirable to replace electronic components within a PC card, such as when a battery runs down or when a card fails inspection before shipping. With the prior art PC card designs described above, reopening the card is difficult, and the cover and plastic frame are typically destroyed in the process. Thus, it is desirable to have a PC card which is inexpensive to manufacture and which may be readily reopened and resealed.
The Personal Computer Memory Card International Association (PCMCIA) is an industry group which sets standards for PC cards to ensure interoperability between the cards of different manufacturers. PCMCIA has set forth standards for three different sizes of cards known as Type I, Type II, and Type III cards. In general, however, the construction of PC cards is not governed by the PCMCIA standards. Many known PC card assemblies are relatively weak and can be easily damaged.
There remains a continuing need for improved PC card assemblies. The card must be sufficiently rigid to prevent damage caused by applied torque or bending forces. It is also desirable to be able to reopen the card for replacement of components and to be able to subsequently reseal the card. To be commercially viable, the card must also be capable of being efficiently and inexpensively manufactured.